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icmp(7) Miscellaneous Information Manual icmp(7) NAME icmp - Internet Control Message Protocol SYNOPSIS #include <sys/socket.h> #include <netinet/in.h> s = socket(AF_INET, SOCK_RAW, proto); DESCRIPTION The Internet Control Message Protocol (ICMP) is the error and control message protocol used by the Internet Protocol (IP) and the Internet Protocol family. It may be accessed through a raw socket for network monitoring and diagnostic functions. The proto parameter to the socket call to create an ICMP socket is obtained from the getprotobyname() function. ICMP sockets are connectionless, and are normally used with the sendto() and recvfrom() functions. The connect() function may also be used to fix the destination for future packets, in which case the read() or recv() and write() or send() functions may be used. Outgoing packets automatically have an IP header prepended to them (based on the destination address). Incoming packets are received with the IP header and options intact. ERRORS If a socket operation fails, errno may be set to one of the following values: The socket is already connected. This error occurs when trying to establish connection on a socket or when trying to send a datagram with the destination address specified. The destination address of a datagram was not specified, and the socket has not been connected. The system ran out of memory for an internal data structure. An attempt was made to create a socket with a network address for which no network interface exists. RELATED INFORMATION Functions: send(2), recv(2) Files: netintro(7), inet(7), ip(7) delim off icmp(7)